seaweeds in the aquarium Part II

Time for the second post on the topic of seaweeds in the aquarium and I will write a part III as well.

4. What conditions are right for seaweeds?

The short answer is: I don’t know yet (and they will vary for different species). I have some clues that add up to a longer answer though. Obviously light is an important factor. Most tanks come with actinic (blueish) light representative of deeper waters. The seaweeds I collect are from shallow water (rock pools) and so are adapted to whiter daylight (as in freshwater planted tanks). I have played around with lighting (see this post) but not in a very systematic way and so am not too sure about what wavelength and intensity is best. Another factor that is important is sufficient wave action. Before I used a Tunze nanostream to create extra flow, I noticed that detritus and algae could settle on seaweeds, see this picture of Serrated wrack Fucus serratus taken from an older post:

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High nutrient levels could benefit some microalgae more than they benefit macroalgae (seaweeds) as is the case for plants in fresh water aquariums and could lead to problems. Another factor that must be very important is temperature. I do not have a chiller and my tank is around 25C (higher than room temperature because of the lighting). Seaweeds from rock pools must have not much problems tolerating this temperature for hours on end, but many might have a problem with it for months on end. I therefore will probably buy a chiller next year…  One very interesting parameter that I have not yet seriously considered is CO2. CO2 can be a limiting factor in photosynthesis, that is why many fresh water aquarium keepers add it (in gas or liquid form) to promote plant growth. I found a very interesting article on the role of CO2 in reef aquariums by a very clever chemist named Randy Holmes-Farley. It could be that CO2 is limiting for seaweeds in my aquarium as well and I’ll definitely need to do some pH tests to find out whether this could be the case. The article lists a table with relative rates of photosynthesis at pH 8.7 compared to pH 8.1 for a number of seaweeds. This is 57% for my favorite seaweed Bushy rainbow wrack Cystoseira tamariscifolia. Very interesting stuff indeed and I shall investigate!

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seaweeds in the aquarium Part I

After some musing on animals that I had good- (here and here) or bad (here) experiences with during the past year-and-a-bit that I have my aquarium, I thought it would also be good to take stock of my experiences with seaweeds. Not many people have temperate marine aquariums, and only few of those who do seem to focus on seaweeds. That is understandable, because it is hard keeping seaweeds! I currently have almost no seaweeds in my tank, as I wanted a break from the problems I had with die backs and resulting detritus. Below a picture of my 130 liter aquarium at its prettiest (see this post); unfortunately it did not look that way for long (see this post):IMG_1981Although keeping seaweeds in the aquarium is difficult, they are so beautiful, diverse and abundant that it is definitely worthwhile to try. The range of shapes and colors is much greater than that of the vascular plants in freshwater tanks. Also, the fact that so few people seriously try to grow different seaweeds in their tank makes it an extra interesting challenge. My fellow aquarists reading this will agree that it is great to look at a ‘finished’ tank, but building it up and experimenting to ‘get it right’ is an integral part of the fun. Keeping a native tank means that you can collect yourself which is a great activity in itself (and free). being able to observe organisms in their own habitat also gives you some clues on how to best keep them in the aquarium. Anyway, below my personal- and somewhat disjointed thoughts on the topic of keeping seaweeds in the aquarium (with some links to previous posts). Quite a lot to write about so I’ll save some pondering for a part II.IMG_0304

1. Many Seaweeds are seasonal

Coming back to the same rock pools over the course of the year, it is very striking to see the composition of seaweed species change. Some species are annuals and always there (although sometimes somewhat overgrown and smaller), but many species are only abundant for a season or even less than that. For example, Dumont’s tubular weed Dumontia contorta was abundant only in early spring this year, whereas Codium tomentosum has just appeared now and will disappear come spring. This must be due to adaptation to annual variations in temperature and daylight (and competition with other species that are present in different months). Although light and temperature conditions can be kept constant in the aquarium, seaweeds are likely ‘programmed’ to thrive at specific times of the year. So in contrast to fresh water planted aquariums where plants just grow and need occasional trimming but otherwise stay the same, marine planted tanks never stay the same. A good example of how a tank can change over time is the series of monthly pictures taken by Jon Olav of his Norwegian native aquarium. I guess for some people, the unpredictability of seaweeds is a downside, not an upside.

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2. ‘Planting’ Seaweeds is difficult

The above picture is of Grape pip weed Mastocarpus stellatus. Like many seaweeds, it is very firmly attached to the rocks. Ripping it off results in a handful of separate fronds which will just float around when transferred to the aquarium. Such species (see here for another example) can only be brought over to the aquarium attached to a rock. Some species readily grow on smaller rocks (Solier’s red string weed often is washed up attached to shells) but others don’t. It is possible with suitably shapedseaweeds to weigh them down using a piece of string and a pebble. (I am not sure about the lead weights used to weigh down plants in freshwater aquariums; on one hand lead is toxic, but on the other hand a layer of lead oxide will form around the weight which prevents leaching. Leaching should be less of a problem in salt water which is slightly alkaline anyway. I’ll stick with pebbles in any case!) Some seaweeds on Castle beach in Falmouth when pulled from the substrate take with it a shard of rock, which makes it easy to anchor them in the aquarium (check):IMG_1746

3. Seaweeds can get eaten

Herbivores, such as snails or prawns can start munching on some seaweeds, especially flat greens and reds seemed vulnerable. Perhaps if you provide enough food, they will leave the seaweeds alone (but you risk overfeeding and the disasters that come with that of course). If you are really into your seaweeds, you could also choose to ditch such critters.IMG_1319

Two starfish videos

I have started a youtube ‘An Bollenessor’ account to be able to embed some of my short iPhone videos here*. First my favourite the Cushion star Asterina gibbosa. My aquarium is more or less empty at the moment, but I still have five of these around. A short movie made with my olloclip macrolens showing how these little starfish move about using their tube feet:

I went out snorkeling yesterday in the mouth of the Helford river (in the rain). A very beautiful spot, I’ll post some pictures of it when I am back and it is sunny. It was high tide and the visibility was bad so I had to dive five meters or so to have a closer look at the Seagrass. I did not see that much but I did spot a Sand star Astropecten irregularis for the very first time. A very beautiful starfish with purple tips and very long tube feet. I took it home and placed it in the aquarium, after which it did what it does best: digging itself in:

*= I use Microsoft Moviemaker to upload files, so had to use my Microsoft account in addition to my Google account, a bit of a hassle. Anyway, it should be easier next time now everything has been set up. For the next videos I will make sure to clean the glass. I probably also should buy a gorillapod to keep my phone still.

top ten animals for the unchilled aquarium: 5 – 1

OK, part two of my list of fun and easy species to keep in an unchilled native marine aquarium (see here for numbers 10-6). I will later post about species to avoid, and of course also about easy seaweeds to keep.

5: juvenile crabs

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Crabs are active and interesting to watch, however, in a community tank they should not be too large as they can be quite destructive as well. Juvenile Shore crabs Carcinus maenas are an option, or a variety of crab species that stay small, such as Pirimela denticulata (I am not too sure what species the above pictured crab is, but it is still doing well four months after collecting it).

4: Squat Lobster Galathea squamifera

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Squat lobsters Galathea squamifera can be a bit shy but are entertaining to watch as they scuttle about. Very common under rocks in silty areas.

3: Snakelocks Anemone Anemonia viridis

IMG_0102Very pretty and common anemones that are easy to keep. Beadlet anemones Actinia equina and Strawberry anemones Actinia fragacea survived in my aquarium as well but they seemed to shrink a bit over time rather than grow and these species can retract their tentacles which looks less nice. I did not specifically feed my anemones by dropping artemia or food pellets on them. The photosynthetic capabilities of Snakelocks anemones due to their algal symbionts probably makes it easier for them to thrive when food is relatively scarce. Beware for the tentacles of larger individuals though, as they can sting!

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2: Common prawn Palaemon serratus

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Prawns* have been a rage in tropical freshwater aquariums for years but people forget that there are very pretty ones right in our seas. I must admit I have not got round to checking rostrum (the ‘nose’) structures to differentiate between several closely related Palaemon species, but I think I have the Common prawn. They are always foraging and flock to any new object in the aquarium to check for edible bits. If the pumps are switched off they will swim and compete with the fish for food.

* or shrimp, these two names can mean different things in different English-speaking countries. In other languages ,like my native language Dutch, we only have a single word (garnaal) for these critters

1: Cushion star Asterina gibbosa

IMG_0356My numbers 2, 3 and 4 could have been number 1 as well, but I ended up picking the very common Cushion Star. Although grey and just an inch in size, these quintessential rock pool inhabitants are active, hardy and just plain cool!

new sand

Welcome to this most obscure of blogs, my dear reader. The aquarium is a bit of a mess at the moment for a variety of reasons. First of all there are a lot of algae growing; I have a bag with Rowaphos hanging in the back compartment to remove phosphates but this does not seem to help much (I have had good experiences with before though). Second, one of my pumps broke and so filtration runs at half capacity. Third, the mixed success of planting many different seaweeds has left loads of detritus in the tank. I have made large water changes which helped a bit. An additional tank for experimenting would be nice to have… Fourth, I have been unlucky with some of the seaweeds: the Wireweed grew really well, but the large size meant it caught a lot of the current and was easily dislodged. The Dudresnay’s whorled weed Dudresnaya verticullosa was growing really well (see here) but broke off from the rocks and could not be replanted:

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I could not attach the fine red seaweed (see last post) either and did not want to have it floating around so I have removed it. My nice red seaweed streaming from the pump outlet, most probably Devil’s tongue weed Grateloupia turutu (as the name indicates, another invader from the Pacific), broke of. A crap picture of both weeds:

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I changed the white gravel with finer, beige Maerl gravel (Cornwall’s equivalent of coral sand, see previous post) here placed in a bowl for contrast:

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I released my Shanny as well as the largest of the two Rock gobies. The former attacked to many of the snails (it was getting a bit of a mollusc graveyard) and the latter was just too voracious in general. The final straw was seeing it swimming around with half a Worm pipefish sticking out of its mouth (I still have a bunch of those). The Shore rockling did not survive, but I caught a glimpse of the Shore clingfish when I removed some of the rocks from the aquarium. The juvenile albino Edible crab (if that’s what it is) and the European sting winkle Ocenebra erinaceus I recently caught both still do well, as is a juvenile Shore crab Carcinus maenas:

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The Netted dog whelk Hinia reticulata is not one of the most impressive looking snails, but they do very well in the aquarium, burrowing and moving around:

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I am not sure whether replacing one of the actinic lamps with the daylight lamp was such a great idea, the tank looks too yellowish now, especially with the Maerl sand…However, I will stick with it and see whether it helps future attempts to successfully keep Bushy rainbow wrack Cystoseira tamariscifolia (i.e. to retain it’s iridescence). If not, I’ll go back to the original lighting. I will not do too much with the aquarium in the near future as I want to get rid of the algae first. There are not many critters in the tank, which should help (I have only introduced a nice big Snakelocks anemone Anemonia viridis recently). I will do some more water changes and order a new pump. Only then will I slowly start experimenting with seaweeds again.

I am still unsure about the chiller, but with the weather getting warmer it might be more than just a luxury to have one. Apart from the price, it standing on the floor next to the aquarium with tubes sticking out is what I don’t like about the idea though. It will also not be silent, but perhaps I could get away with disabling the noisy hood fans, resulting in an overall quieter aquarium. The stripped-down tank (note that the red encrusting algae/seaweeds at the top of the tank have died (turned white) as they were exposed for a couple of hours when changing water):

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new lighting

My new 55 watt fluorescent Philips daylight lamps arrived last week. The first picture shows the two standard 10.000 K actinic lamps that come with the Red Sea Max 130D; the second picture shows the two new daylight lamps. I found he light coming from the actinic lamps always looking rather harsh, but the daylight lamps looked awfully yellow. I decided to compromise between photosynthesis and aesthetics and go for one of each type (third picture):

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As you can see, the Wireweed and Dudresnays whorled weed are doing very well.

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The 10.000 K lamp (top) and the 6500 K lamp. Contrary to my expectation, the temperature dropped using the new lighting: from 25C to 23C, good! I have ‘planted’ some Furcellaria lumbricalis, let’s see what it does:


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Yesterday I discovered a big patch of Bushy rainbow wrack Cystoseira tamariscifolia on Castle beach in Falmouth (I noticed that this seaweed grows quite high on the shore at this location). I should have brought a small plant back to test with the new lighting (and lower temperature and salinity) but I reckoned it would be best to wait a bit until I have a chiller as well to get all conditions right. Hmmm, maybe I’ll go back today…

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tank update

Time for an update on the tank. Switching to two lamps instead of one looks good but has not brought the iridescence of the Bushy rainbow wrack back. I could not resist putting a new specimen in. Iridescence is defined as the property of certain surfaces to appear to change color as the angle of view or the angle of illumination changes. Left: viewed from below, right: viewed from above.

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I noticed that the underside of the rock the weed was attached to harbored a nice little strawberry worm, but before I could photograph it, the large rock goby gulped it down. It is noticeable that the fish have full bellies after putting in a new piece of seaweed, which is no surprise as there is so much growing on and in it.I have seen the very cute amphipod Caprella acanthifera which looks like a tiny, marine cross between a praying mantis and a caterpillar, but since they did not come not near the glass I could not get a good shot. I have seen one Cushion star Asterina Phylactica as well, which looks nicer than the light grey Asterina gibbosa I have. I also noticed a couple of Cerithiopsis tubercularis (3-4 mm):

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The tank is completely full of snakelocks anemones, hundreds maybe:

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In the foreground an Idiotea isopod; there are many of these sitting on seaweed branches and occasionally swimming around, although most of them will probably be eaten by now. Finally, three seaweeds have started to grow from the pump outlets. Dudresnay’s whorled weed, a fine purple weed and a broadleaved red seaweed. I have placed adult plants of the latter species (30 cm or so)  in my aquarium before, but these were quickly eaten. It is either a type of laver or dulse, but I am not sure. It has also settled on the glass, but seldomly grows ‘leaves’ on there. Growing in the water current protects the weeds from predation from shrimps, let’s see how big they can grow!

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trouble in paradise

A very corny title indeed but wordpress recommended trying to come up with catchy post titles so that’s my excuse… I was very pleased with the way the tank looked after my first serious session of aquascaping. My satisfaction of course did not last for too long. First, I noticed that the water turned cloudy the next day as the result of a bacterial bloom. I quickly changed two buckets of sea water and turned on the skimmer (the Red Sea Max stock skimmer makes an unholy noise and so is usually only on at night (if I don’t forget)). This seemed to help and the water turned clear again within two days or so. I had not expected a bloom to occur, as I added seaweeds (removing nutrients) rather than animals (adding nutrients), plus I had not been feeding frozen artemia for a while. Anyway, this problem has been solved. It is probably better next time to change the tank in multiple steps rather than making wholesale changes. I next noticed the Harpoon weed starting to whither. This has happened before so it was not a real surprise. A close-up of the Harpoon weed when it was still looking good:

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Some Slender-beaded coral weed made it into the aquarium attached to other weeds. As expected, this weed also died and turned white:

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I next noticed that the branchlets of the Red grape weed turned from a dark purple-brown into a fresh green. Although pretty, that this was not a change for the better was obvious when upon touching the plant many of the branchlets were shed. I removed this plant before this debris would clog the filter.

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The main thing that disappointed me though is that the Bushy rainbow wrack steadily lost its iridescent colors and turned into the brown of the other Bushy wrack species. The fact that I had bright blue, green and purple in my aquarium was the most amazing thing about it. Before and after pics:

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I reckon this has to do with the light spectrum not being right. The colors are reminiscent of the Jade vine from the Philippines. Its coloration is the result of two pigments, malvin and saponarin, being present at a specific ratio at a specific alkalinity (wikipedia again). Both Jade vine and Bushy rainbow wrack seem to be fluorescent to my non-expert eye, although a quick search on google did not give me anything on fluorescent plants. Anyway, I will make it my goal in life to find the light conditions that bring back these colors!

To properly experiment with any seaweed it will be desirable to be able to vary the light spectrum and intensity. Probably the best way to go is LED lights, although I am not very knowledgeable about lighting yet and it is all quite complicated (LUX, PAR, micro-Einsteins, Kelvin ratings…) It is also not clear to me if (affordable) LED options are on the market that actually allow you to adjust the light spectrum. I will ask around on some forums. It could also be that the light intensity is not right; I have only used one of the two fluorescent T5 lamps provided with the Red Sea Max 130D as I found the lighting too bright when I started. However, now the tank is full of seaweeds, more of the light will be absorbed and it might not look like I have a tanning bed in the living room. I will pop the other light in and see. The RSM lights are so-called 50/50 lamps that give 50% ‘day light’ and 50% ‘actinic’ (blue) light. Who knows some extra actinic light will help. I need to read up on the subject. There must be other factors as well. For instance room temperature might be too high for some species (this reminds me I need to buy a thermometer!). The Bushy berry wrack, False eyelash weed and Wireweed seem to be doing OK though. Here a picture of Wireweed:

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The tank a week after planting:

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some serious aquascaping

With the seaweeds collected, it was time to plant my aquarium. This time I took a more serious approach, I planted lots. Many of the seaweeds had bits of rock attached to their holdfasts which made it easy to anchor them in the gravel. Two of the weeds I tied to rocks with a piece of elastic band, easy peasy:IMG_1981

View from the left side. False eyelash weed Calliblepharis jubata in the front, tall Wireweed Sargassum muticum and in the middle some coarse brown sea weed which almost looks like a dead conifer. This is probably Bushy berry wrack Cystoseira baccata: IMG_1990

An expanded view, on the right some Red grape weed Gastroclonium ovatum, in the middle the red pluck of Dudresnays whorled weed Dudresnaya vertillicata that I already had:

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A goby amidst the False eyelash weed lying on top of what may be Purple claw weed, I am not sure:

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The magnificently coloured Bushy rainbow wrack Cystoseira tamariscifolia covered in green Snakelocks anemones Anemonia viridis. In the foreground the pink Slender-beaded coral weed Jania rubens and Harpoon weed Asparagopsis armata.

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A close-up of the Bushy rainbow wrack. Other plants were bright green or purple. I never knew that seaweeds existed with these iridescent colours. In fact, when I glimpsed one for the first time in a rock pool I disregarded it because I thought it was some seaweed covered in oil slick! These weeds are also have a very cartilaginous texture which give them more of an animal-like appearance.

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I discovered several small whitish Sea lemon nudibranchs Archidoris pseudoargus, very cool.

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first attempts at aquascaping

I am not sure if I like the term aquascaping much because of it’s connotations with gardening and I like a more natural look. However, aquascaping is the general term for arranging plants in an aquarium nowadays and that is what I attempt to do as well with seaweeds. (Also, I cannot pretend that my tank looks particularly like a real rock pool…). Anyway, I will post some more thoughts on the topic of aquascaping, marine or fresh water, later but for now just wanted to show some of the first attempts at planting my aquarium, It is challenging to make any tank look ‘right’, but I found it particularly hard to recreate a rock pool feel. I soon found out that I did not have enough rock in the tank and so hauled some *heavy* ones from a nearby beach. The bare tank:IMG_0551

Some wrack added (I cannot remember what species and cannot tell from the picture, it did well though). A strawberry anemone Actinia fragacea on the right.IMG_0593

Another version with Serrated wrack Fucus serratus (left), a small mop of Dudresnay’s whorled weed Dudresnaya vertillicata (far left) and some Solier’s red string weed Soliera chordalis (middle and right). A bit messy:IMG_0362

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A worm pipefish, dog whelk and hermit crab in front of the serrated wrack. There is a lot of algal growth and detritus on the wrack. (I have since bought a circulation pump to keep detritus in suspension so it can go into the filter, more about that later).IMG_1285Another go. The nice thing about having an aquarium with native species is that you can collect them yourself, which is half the fun (and free), and when something does not work out you just chuck it back and try something else.  The green seaweed is velvet horn Codium tomentosum, the long brown seaweed is wireweed Sargassum muticum. Both did well, the wireweed grew quite fast, perhaps not a surprise as it is an invasive species in the UK. The red seaweed on the left is dulse Palmaria palmata, on the right harpoonweed Asparagopsis armata. The harpoonweed was not exactly thriving and the dulse was quickly eaten by the prawns:IMG_1319IMG_1701Recently, I noticed the Dudresnay’s whorled weed (love that name) sprouting from the rocks everywhere. This happened some months after removing a pluck of this weed from the aquarium. Up till then I had just planted seaweeds, but having them establish spontaneously I had not seen before. Most of the newly established weeds are only a couple of centimeters and do not seem to grow very fast, but the two weeds pictured above grew to 10 centimeters in a couple of weeks. Perhaps very local conditions in the aquarium matter.